1. Field of the Invention
The present invention relates to elastomer-coated bias fabrics of the type employed as reinforcement in such industrial products as power transmission belts, hoses, tires and the like and, more particularly, to neoprene-coated bias-cut reinforcement fabrics having one tacky face; and to a method and apparatus for producing the same.
2. Prior Art Statement
Bias-cut fabrics which have previously been coated and impregnated with an uncured, tacky, elastomeric compound such as a synthetic elastomer have conventionally been used in the production of power transmission belts, hoses, and the like as a protective cover and reinforcement. It is the common practice to combine the pre-coated bias-cut fabric with the carcass, substrate or core of the product during the vulcanizing operation such that heating cures and adhesively bonds the fabric to the rubber base of the product.
Elastomer-coated bias-cut fabrics have been the subject of a number of U.S. Patents including:
U.S. Pat. No. 1,323,212 (1919) to Bulley PA1 U.S. Pat. No. 3,784,427 (1974) to Griffin PA1 U.S. Pat. No. 3,832,210 (1974) to Rohlfing PA1 U.S. Pat. No. 4,283,455 (1981) to McGee PA1 U.S. Pat. No. 4,062,989 (1977) to Long PA1 U.S. Pat. No. 4,116,159 (1978) to Long PA1 U.S. Pat. No. 4,205,559 (1980) to Long et al PA1 (a) pre-impregnating a bias fabric with an elastomeric latex composition, PA1 (b) transversely stretching the pre-impregnated fabric in the widthwise direction, PA1 (c) applying a flowable elastomeric latex composition to both faces of the stretched fabric such that the elastomeric latex composition substantially penetrates the interstices of the fabric, PA1 (d) drying the fabric to solidify the elastomeric composition thereon, PA1 (e) applying a flowable tackified, carboxylated elastomeric latex composition over the neoprene coating on one face only of the coated fabric, and PA1 (f) drying the fabric to solidify the carboxylated elastomeric composition and provide a tacky coating. PA1 means for moving a bias fabric in a generally horizontal path of travel, PA1 means for immersing the fabric in an elastomeric composition as it moves along said path of travel, so as to impregnate the fiber bundles in the fabric with the elastomeric composition, PA1 means for transversely stretching the fabric and maintaining the fabric in a stretched condition as it moves along said path of travel, PA1 a first applicator means positioned beneath and extending across the path of travel for continuously applying a layer of an elastomeric composition to the bottom surface of the fabric as the fabric moves along the path of travel, PA1 a second application means positioned above and extending across the path of travel for continuously applying a layer of an elastomeric composition to the top surface of the fabric as it moves along the path of travel, PA1 a first scraper means positioned beneath the path of travel and downstream of the first and second applicator means and extending across the path of travel for continuously smoothing the layer of elastomeric composition on the bottom surface of the fabric to the desired thickness and removing excess composition, PA1 a first drying means positioned immediately downstream of the first scraper means for drying the coated fabric, PA1 a third applicator means positioned beneath and extending across the path of travel for continuously applying a layer of a tackified elastomeric composition to the bottom surface of the fabric as it moves along the path of travel, PA1 a second scraper means positioned beneath the path of travel and downstream of the third applicator means for continuously smoothing the layer of elastomeric composition on the bottom surface of said fabric to the desired thickness and removing excess composition, and PA1 means for collecting the coated fabric.
as well as the following U.S. Patents to the present inventor:
Bulley discloses a rubber impregnated bias cut fabric for use in a tire carcass.
Griffin discloses a method and apparatus for manufacturing an elastomer-coated bias cut fabric wherein a tubular woven fabric is cut spirally at a 45.degree. angle to produce a continuous sheet of fabric which is impregnated with a curable binder and transversely stretched on a tenter frame to increase the complementary angle of the warp and weft threads. The binder is cured or otherwise hardened to stabilize the fabric and is subsequently immersion impregnated with the elastomeric composition such as neoprene dissolved in a solvent, dried and cut into strips for application to V-belt cores.
Rohlfing discloses a bias cut fabric which is manufactured from a tubular fabric which is woven such that when the fabric is cut on the 45.degree. bias there is a minimum of selvage.
McGee discloses a process which parallels that of Griffin wherein the fabric is impregnated with an elastomeric composition containing a pigment which is removed as the edges of the fabric are abraded to reveal the white threads of the fabric which can then be interpretted as a sign of wear.
Long '989 discloses a method and apparatus for uniformly coating and impregnating a bias-cut woven fabric with a tacky elastomer as the fabric is pantographed on the tentering frame. The fabric is coated without stabilizing the fabric with additional binder by sequentially applying a viscous elastomeric coating to the lower and upper faces of the fabric inwardly of the edges while the fabric is stretched on a tenter frame and by smoothing the coatings to a uniform thickness.
Long '559 is directed to a neoprene coating composition useful in the Long '989 process wherein a carboxylated neoprene is tackified with a high boiling aromatic oil.
Long '159 is directed to a coating head for applying viscous coatings such as elastomeric latices to a moving woven web. The coating head employs a pair of elongate manifolds extending across the web which simultaneously coat both faces of web by extrusion and thereby ensure penetration of the interstices of the fabric by the coating composition.